1. Field of the Invention
This invention relates generally to an improvement to the impingement system of the M-16 and AR-15 rifle platforms, and more particularly to the replacement of the impingement system with a direct drive system.
2. Description of the Related Art
Replacing the impingement system of the M-16 or AR-15 is not a new idea. Many attempts have been made to do so. It is well known to those who use this rifle and those in industry that the M-16 is notorious for fouling and jamming due to the design requiring that the discharge gas be directed into the bolt carrier to activate the bolt and discharge the spent shell.
The disadvantages of the OEM impingement system are well known, primarily due to the hot, dirty gasses being directed into the bolt carrier and receiver. The heat alone tends to wear parts down, exposing this area to thermal cycling. With the addition of soot or carbon from the expelled gasses, the moving parts within the bolt carrier and receiver are exposed to a hostile environment. This is exacerbated by the constant need to lubricate this entire area; the oil serving to trap particles and carbon. This combination of factors cause the parts to break, wear, or operate improperly. The areas of failure can include the fouling and wear of the gas rings, loosening of the ejector and extractor springs causing the spent shell to not be ejected properly, the bolt carrier is prevented form traveling properly within the receiver, as the chamber becomes fouled and increases in temperature causing the entrapment of the spent shell, the melting of the gas tube causing a restriction of flow to the bolt carrier and subsequent failure. Basically, to ensure the proper operation of the rifle, it must be cleaned and continually lubricated. With many parts to keep track of, consistent cleaning is more difficult in the field.
Others have developed systems to replace the OEM impingement system. Some require that significant portions of the rifle be modified or replaced, such as the barrel and parts within the receiver. These systems have obvious drawbacks. The cost of replacing the barrel and other parts is substantial and unnecessary. If machining is required to install the system, the user must send the rifle to a machinist to be modified, added time and expense to the process, and potentially introducing error with each independent machining process.
Some manufacturers have designed systems that do not require the replacement of the barrel and are an improvement over the OEM and previous systems, such as the system manufactured by Land Warfare Resources Corporation (LWRC). The problems with these existing systems arise during assembly or disassembly for cleaning and inspection. These systems require that a substantial portion of the system be removed to access the rod assembly or the gas plug located in the gas block. Often, it is required that the hand guard be removed, the gas block loosed and slid muzzleward so that the gas plug is free to be removed and the rod assembly is accessible and also free. Existing systems must also segment the rod into several sections, so that the assembly can be removed from the tight quarters beneath the hand guard. A single piece or continuous rod is not possible in this system. A single rod would not have the necessary clearance to be removed in tact.
What is needed and not heretofore provided by the existing art is a direct drive retrofit system to replace the impingement system of the OEM rifle. What is further needed is a retrofit system that does not require machined modification or replacement of the barrel and other primary parts of the rifle. What is further needed is a retrofit system that is easily assembled and disassembled in the field, by minimizing complexity and the overall number of parts. What is again needed is a retrofit system that can be removed for inspection and cleaning without substantial disassembly of neighboring parts, such as the gas block or hand guard.